If you really believe a word you've just written, here's my suggestion. Change the page so that by default you're not joined up to the VIP program and shoppers have to specifically opt-in. If the text is as clear as you claim, you'll still get roughly the same join up rate because the deal is being made is brilliant and it's perfectly clear what's happening, right?
A note on this: I do believe the website to be a scam and parent to be obtuse or lying, but for the specific case of your comment studies have proved that people are more likely to stick with the default choice made for them, so you example wouldn't work. Even if the two offers were providing an absolutely identical end value, the default one would have more adoption.
